1. Field of the Invention
The invention relates to a method for accessing a memory card, and more particularly to a method for accessing a memory card by a control unit using less pins.
2. Description of the Related Art
A Secure Digital (SD) card is a non-volatile flash memory card format developed by Matsushita, SanDisk, and Toshiba for use in portable devices. A Memory Stick (MS) card is a removable flash memory card, launched by Sony, and is also used in general to describe the whole family of Memory Sticks. In addition to the original Memory Stick, the family of Memory Sticks also includes the Memory Stick PRO (MSP), a revision that allows greater maximum storage capacity and faster file transfer speeds. A MultiMediaCard (MMC) card is a flash memory card unveiled by Siemens AG and SanDisk.
Typically, the SD, MS, MSP or MMC memory card is used as a storage media and is widely used in digital cameras, handheld computers, PDAs, mobile phones, GPS receivers, TVs, DVD players, video game consoles and so on. When compared with the MS, MSP, or MMC memory cards, unlike the MS, MSP, or MMC memory cards, the SD card may have a write protection feature/function, wherein the SD card would be write-protected and in a read-only state when its write protection feature/function is enabled.
At present, electronic devices may provide a multi-in-one socket to support different types of memory cards (such as the SD, MS, MSP or MMC memory cards) for convenience, thus the complexity of control designs and hardware costs are increased.